Chronic total occlusion device with variable stiffness shaft

ABSTRACT

The present invention relates generally to a device for adding stiffening support to a guidewire so as to enable the guidewire or device to pass through a chronic total occlusion. A method for passing a guidewire through a chronic total occlusion is also disclosed.

FIELD OF THE INVENTION

[0001] The present invention relates to devices for performingintravascular procedures. More particularly, the present inventionrelates to devices for adding support to a guidewire so that theguidewire may be passed through a chronic total occlusion.

BACKGROUND OF THE INVENTION

[0002] The use of intravascular catheters has become an effective methodfor treating many types of vascular disease. In general, anintravascular catheter is inserted into the vascular system of thepatient and navigated through the vasculature to a desired target site.Using this method, virtually any target site in the patient's vascularsystem may be accessed, including the coronary, cerebral, and peripheralvasculature. Examples of therapeutic purposes for intravascularcatheters include percutaneous transluminal angioplasty (PTA) andpercutaneous transluminal coronary angioplasty (PTCA).

[0003] Intravascular catheters are commonly used in conjunction with aguidewire. A guidewire may be advanced through the patient's vasculatureuntil it has reached a target location. Once in place, a catheter may bethreaded onto the guidewire and urged distally until the distal end ofthe catheter reaches a target location.

[0004] When in use, the guidewire enters the patient's vasculature at aconvenient location and then is urged to a target region. The path takenby a catheter through the vascular system is often tortuous, requiringthe guidewire to change direction frequently. In order for the guidewireto conform to a patient's tortuous vascular system, it is desirable thatit be very flexible, particularly near the distal end.

[0005] The guidewire will often confront a stenosis when passing throughthe vasculature. In addition, the stenosis may completely block thevessel as is the case with a chronic total occlusion. The success of theprocedure often depends on the ability to insert the guidewire throughthe chronic total occlusion.

SUMMARY OF THE INVENTION

[0006] The present invention pertains to a chronic total occlusiondevice that may add support to a guidewire so that the guidewire maypass through a chronic total occlusion. The chronic total occlusiondevice may comprise an outer tubular member having a proximal end, adistal end, and a lumen extending therethrough. The proximal end may beconnectable to a manifold and the distal end may include a distal tip.

[0007] An inner tubular member may be disposed within the lumen. Theinner tubular member may comprise a proximal end, a distal end, and aninner lumen extending therethrough. The inner lumen may be adapted sothat a guidewire may be disposed therein.

[0008] An annular space may be formed between the outer tubular memberand the inner tubular member. A stiffening member may be disposed withinthe annular space. The stiffening member may comprise a distal head anda proximal tail. The proximal tail may be more stiff than the distalhead. In an exemplary embodiment, the stiffening member is movablerelative to the outer tubular member. The manifold may comprise a meansfor controlling the stiffening member.

[0009] The outer tubular member may further comprise an expandableregion. The expandable region may further comprise a first region and asecond region. The first region may include a first outside diameter.The second region may include a second outside diameter that, whenexpanded, is generally smaller than the outside diameter of a typicalangioplasty balloon. According to this embodiment, the stiffening membermay comprise inflation medium, liquid, or gas. Additionally, themanifold may include an inflation medium pump capable of pumping theinflation medium into the expandable region so that the chronic totalocclusion device may add stiffness to the guidewire, dilate the vessel,anchor the device, or center the guidewire.

[0010] The chronic total occlusion may further comprise a marker band.The marker band may be disposed proximal of the distal tip.Alternatively, the marker band may be disposed at the distal tip.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a side view of a chronic total occlusion deviceaccording to a preferred embodiment of the invention disposed within avessel;

[0012]FIG. 2 is a cross sectional view of a chronic total occlusiondevice according to a preferred embodiment of the invention;

[0013]FIG. 3 is a cross sectional view of an alternate embodiment of thechronic total occlusion device shown in FIG. 2;

[0014]FIG. 4 is a cross sectional view of a second alternate embodimentof the chronic total occlusion device shown in FIG. 2;

[0015]FIG. 5 is a cross sectional view of an alternate chronic totalocclusion device according to a preferred embodiment of the invention;

[0016]FIG. 6 is a cross sectional view of an alternate embodiment of thechronic total occlusion device shown in FIG. 5; and

[0017]FIG. 7 is a cross sectional view of a second alternate embodimentof the chronic total occlusion device shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following description should be read with reference to thedrawings wherein like reference numerals indicate like elementsthroughout the several views. The detailed description and drawingsillustrate example embodiments.

[0019]FIG. 1 is a side view of a chronic total occlusion device. Alongthe length of a blood vessel 10, a chronic total occlusion 12 may bepresent. Chronic total occlusion 12 is understood to be a partial orcomplete blockage of blood vessel 10 and may comprise a calcifiedlesion, an atherosclerotic lesion, a stenosis, etc. Chronic totalocclusion 12 may occlude blood vessel 10 so as to substantially preventthe passage of a guidewire 14 therethrough. In order for guidewire 14 topass chronic total occlusion 12, it may need added stiffening support.Stiffening support for guidewire 14 may include a chronic totalocclusion device 16.

[0020] Chronic total occlusion device 16 may be used to stiffenguidewire 14 in conjunction with a number of medical procedures. Chronictotal occlusion device 16 may be used with a device or method thatutilizes an intravascular guidewire. For example, chronic totalocclusion device 16 may be used during percutaneous transluminalangioplasty (PTA), percutaneous transluminal coronary angioplasty(PTCA), atherectomy, or other vascular procedures.

[0021]FIG. 2 is a detailed view of chronic total occlusion device 16.Chronic total occlusion device 16 may comprise an outer tubular member18 having a proximal end 20, a distal end 22, and a lumen 24 extendingtherethrough. The length of chronic total occlusion device 16 may beabout equal to a typical angioplasty catheter. For example, chronictotal occlusion device may be about 50-200 cm long.

[0022] Outer tubular member 18 may be comprised of materials including,but not limited to, metals, stainless steel, nickel alloys,nickel-titanium alloys, nitinol, thermoplastics, high performanceengineering resins, fluorinated ethylene propylene (FEP), polymer,polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC),polyurethane, polytetrafluoroethylene (PTFE), polyether-ether ketone(PEEK), polyimide, polyamide, polyphenylene sulfide (PPS), polyphenyleneoxide (PPO), polysufone, nylon, or perfluoro(propyl vinyl ether) (PFA),and combinations thereof.

[0023] Outer tubular member 18 may be subdivided into a proximal segment26 and a distal segment 28. According to this embodiment, proximalsegment 26 may be comprised of CRISTAMID® 11200, which is asemi-aromatic co-polyamide polymer commercially available from Atochemand is the subject of U.S. Pat. No. 4,898,896, hereby incorporated byreference. Distal segment 28 may be comprised of polyether block amide(PEBA). Polyether block amide is commercially available from AtochemPolymers of Birdsboro, Pa., under the trade name PEBAX. Distal segment28 may have increased flexibility relative to proximal segment 26.

[0024] Proximal end 20 may be connectable to a manifold 30. Proximal end20 may be bonded to manifold 30 with an adhesive. Alternatively,proximal end 20 may further comprise a luer adapter that is connectableto manifold 30. Distal end 22 may include a distal tip 32 that may betapered. In an exemplary embodiment, distal tip 32 may be comprised ofGrilamid® (ELY 2694), which is commercially available from EMS-Chemie.

[0025] An inner tubular member 34 may be disposed within lumen 24. Innertubular member 34 may be generally coaxial with outer tubular member 18.Inner tubular member 34 may comprise a proximal end 36, a distal end 38,and an inner lumen 40 extending therethrough. Inner tubular member 34may comprise an inner layer of high density polyethylene (HDPE, namelyMarlex HHM 4903, commercially available from Phillips Petroleum), anouter layer of polyether block amide (PEBAX 7233), and a tie-layer ofPlexar 380 to adhere the layers. Plexar is a known tie layer materialthat is a modified low density polyethylene. Inner layer 34 may bemanufactured by coextrusion of the above materials. Alternatively, innertubular member 34 may be comprised of materials similar to thosedisclosed above for outer tubular member 18.

[0026] Inner lumen 40 may be adapted so that guidewire 14 may bedisposed therein. Inner lumen 40 has an inside diameter appropriate toaccommodate multiple embodiments of guidewire 14 having differingoutside diameters. For example, inner lumen 40 may accommodate guidewire14 having an outside diameter less than about 0.038-0.008 inches.Alternatively, inner lumen 40 may accommodate guidewire 14 having anoutside diameter less than about 0.014 inches. Inner lumen 40 mayfurther comprise a lubricious liner. The lubricious liner may comprisepolytetrafluoroethylene.

[0027] Although inner lumen 40 may have an inside diameter ofappropriate size for many embodiments of guidewire 14, alteration of theinside diameter of inner lumen 40 may occur while maintaining thegenerally small profile of chronic total occlusion device 16 and, thus,the ability of outer tubular member 18 to pass through tight stenoticvasculature. According to this embodiment, the outside diameter of outertubular member 18 may be less than about 0.200-0.500 inches.

[0028] An annular space 42 may be formed between outer tubular member 18and inner tubular member 34. A stiffening member 44 may be disposedwithin annular space 42. Stiffening member 44 may comprise a number ofmaterials similar to those listed above including metals and polymers.In addition, stiffening member 44 may comprise a wire or stiffeningsleeve.

[0029] Stiffening member 44 may further include a distal head 46 and aproximal tail 48. Proximal tail 48 may be more stiff than distal head46. Stiffening member 44 may be movable relative to outer tubular member18. Actuation of stiffening member 44 can, thus, vary the stiffness ofchronic total occlusion device 16 along the length of outer tubularmember 18. For example, actuation of stiffening member 44 may comprisemoving distal head 46 toward distal end 22. Actuation may result inincreased stiffness of chronic total occlusion device 16 near distal end22. Increased stiffness may enable chronic total occlusion device 16 toprovide stiffness support to guidewire 14 so that guidewire 14 may passthrough chronic total occlusion 12.

[0030] Manifold 30 may further comprise means for controlling stiffeningmember 44. Means for controlling stiffening member 44 may include anaccess port to proximal tail 48. According to this embodiment, manifold30 may comprise an opening that may allow a clinician to grasp and moveproximal tail 48 relative to outer tubular member 18. Additional meansfor controlling stiffening member 44 may include a handle assemblycomprising an actuation button, wheel, lever, or slidable object whereinactuation of the means for controlling stiffening member 44substantially results in movement of stiffening member 44 relative toouter tubular member 18. Moreover, the coupling of proximal tail 48 tomanifold 30 may add further support along the length of guidewire 14during, for example, exchange of catheters over guidewire 14 and forexchange of guidewires.

[0031] In use, chronic total occlusion device 16 or alternates thereofmay be used in multiple ways to add support to guidewire 14. Forexample, chronic total occlusion device may be passed over guidewire 14if chronic total occlusion 12 is encountered while steering guidewire 14through blood vessel 10. According to this embodiment, guidewire 14 maybe steered through blood vessel 10 until encountering chronic totalocclusion 12, chronic total occlusion device 16 may be passed overguidewire 14, and chronic total occlusion device 16 (with guidewire 14disposed in inner lumen 40) may pass chronic total occlusion 12. Duringthe step of encountering or passing chronic total occlusion 12, chronictotal occlusion device 12 may pre-dilate blood vessel 10 which may aidfurther dilation, for example, by an angioplasty catheter or stent. Ifdesired, chronic total occlusion device 14 may be withdrawn fromguidewire 14 until a further chronic total occlusion is encountered.Further, an alternative embodiment of chronic total occlusion device 16comprises a single-operator-exchange catheter including a proximalguidewire port proximate distal end 22. The inclusion of the port mayfacilitate easier exchange of catheters along guidewire 14.

[0032] Alternatively, guidewire 14 may be disposed within inner lumen 40while chronic total occlusion device 16 is steered through blood vessel10. According to this embodiment, chronic total occlusion device 16(with guidewire 14 disposed in inner lumen 40) may be steered throughblood vessel 10 so as to more easily pass chronic total occlusion 12when encountered. Similar to what is stated above, this method may beused in accordance with the single-operator-exchange embodimentdisclosed above.

[0033]FIG. 3 is a cross sectional view of an alternate embodiment ofchronic total occlusion device 16 shown in FIG. 2. Chronic totalocclusion 116 is essentially similar to chronic total occlusion device16 except it further comprises a marker band 150. Marker band 150 may bedisposed near distal tip 32.

[0034] Marker band 150 may produce a relatively bright image on afluoroscopy screen during a medical procedure. This relatively brightimage may aid the user of chronic total occlusion device 16 indetermining the location of distal end 22 of outer tubular member 18.Marker band 50 may comprise a number of radiopaque materials including,but not limited to, gold, platinum, and plastic material loaded with aradiopaque filler. Chronic total occlusion device 16 may furthercomprise additional marker bands or may comprise a marker band disposedat a different location. For example, chronic total occlusion device 16may comprise a first marker band (e.g., marker band 150) a fixeddistance from distal end 22 of outer tubular member 18. A second markerband may be disposed on outer tubular member 18 proximally a distancethat is approximately equal to the distance the first marker band isfrom distal end 22.

[0035]FIG. 4 is a cross sectional view of a second alternate embodimentof chronic total occlusion device 16 shown in FIG. 2. Chronic totalocclusion 216 is essentially similar to chronic total occlusion device16 except it further comprises marker band 250 disposed at distal tip32. Marker band 250 may comprise a radiopaque additive that may beimpregnated within distal tip 32. This method of disposing marker band250 at distal tip 32 may help prevent or avoid weeping of the radiopaquematerials into the body of a patient.

[0036]FIG. 5 is a detailed view of an alternate chronic total occlusiondevice. Chronic total occlusion device 316 is essentially similar tochronic total occlusion device 16 except that outer tubular member 318further comprises an expandable region 352 in addition to proximal end320, distal end 322, and lumen 324 extending therethrough. Expandableregion 352 may comprise a balloon. Expandable region 352 may be formedby alternatively processing outer tubular member 318. For example,alternative processing of outer tubular member 318 may include blowmolding, changing dimensions, chemically changing, forming of differingmaterials including materials capable of self-collapsing afterinflation, etc.

[0037] Expandable region 352 may further comprise a first region 354 anda second region 356. First region 354 may include a first outsidediameter 360. Second region 356 may include a second outside diameter358 that, when expanded, may be generally smaller than the outsidediameter of a typical angioplasty balloon. Moreover, first outsidediameter 360 may be generally smaller than second outside diameter 358.Maintaining a generally smaller profile than a typical angioplastyballoon may allow chronic total occlusion device 316 to be steeredthrough stenotic vasculature.

[0038] Stiffening member 344 may be disposed within expandable region352. Stiffening member 344 may comprise inflation medium, liquid, orgas. According to this embodiment, stiffening member 344 can be movedalong outer tubular member 318 to expandable region 352.

[0039] Annular space 342 may be in fluid communication with expandableregion 352. Manifold 30 may further comprise means for controllingstiffening member 344. Means for controlling stiffening member 344 mayinclude an inflation medium pump capable of pumping stiffening member344 into expandable region 352. For example, manifold 30 may include aninflation medium pump suitable for pumping inflation fluid intoexpandable region 352.

[0040] In use, chronic total occlusion device 316 may be usedsubstantially similar to chronic total occlusion device 16. Actuation ofstiffening member 344 may comprise expanding expandable region 352 bypassing stiffening member 344 into expandable region when guidewire 14is disposed within inner tubular member 34. Actuation of stiffeningmember 344 may provide stiffening support to guidewire 14. Passingstiffening member 344 into expandable region may result in little or noexpansion of expandable region 352. According to this embodiment,actuation of stiffening member 344 is understood to stiffen chronictotal occlusion device 316 by adding tension to outer tubular member318. Expandable region 352 may, thus, comprise materials that aresubstantially resistant to expansion.

[0041]FIG. 6 is a detailed view of an alternate embodiment of thechronic total occlusion device shown in FIG. 5. Chronic total occlusion416 is essentially similar to chronic total occlusion device 316 exceptit further comprises a marker band 450. Marker band 450 may be disposednear distal tip 32 or may be disposed proximal of distal tip 32.

[0042]FIG. 7 is a detailed view of a second alternate embodiment of thechronic total occlusion device shown in FIG. 5. Chronic total occlusion516 is essentially similar to chronic total occlusion device 316 exceptit further comprises marker band 550 disposed at distal tip 32. Similarto what is disclosed above, marker band 550 may comprise a radiopaqueadditive that may be impregnated within distal tip 32.

[0043] Numerous advantages of the invention covered by this documenthave been set forth in the foregoing description. It will be understood,however, that this disclosure is, in many respects, only illustrative.Changes may be made in details, particularly in matters of shape, size,and arrangement of steps without exceeding the scope of the invention.The invention's scope is, of course, defined in the language in whichthe appended claims are expressed.

What is claimed is:
 1. A chronic total occlusion device, comprising: anouter tubular member including a proximal end, a distal end, and a lumenextending therethrough; an inner tubular member disposed within thelumen, the inner tubular member having an inner lumen; an annular spacebetween the outer tubular member and the inner tubular member; and astiffening member disposed within the annular space.
 2. The device inaccordance with claim 1, wherein a manifold is disposed at the proximalend of the outer tubular member.
 3. The device in accordance with claim2, wherein the manifold includes means for controlling the stiffeningmember.
 4. The device in accordance with claim 1, wherein the stiffeningmember further comprises a distal head and a proximal tail.
 5. Thedevice in accordance with claim 4, wherein the stiffening member ismovable relative to the outer tubular member.
 6. The device inaccordance with claim 1, wherein the outer tubular member furthercomprises an expandable region.
 7. The device in accordance with claim6, wherein the expandable region comprises a balloon.
 8. The device inaccordance with claim 7, wherein the annular space is in fluidcommunication with the balloon.
 9. The device in accordance with claim6, wherein the expandable region further comprises a first region havinga first outside diameter and a second region having a second outsidediameter.
 10. The device in accordance with claim 9, wherein the firstoutside diameter is less than the second outside diameter.
 11. Thedevice in accordance with claim 9, wherein the stiffening membercomprises a liquid.
 12. The device in accordance with claim 9, whereinthe stiffening member comprises a gas.
 13. A chronic total occlusiondevice, comprising: an outer tubular member including a proximal end, adistal end, a lumen extending therethrough, and an expandable regionhaving a first region having a first outside diameter, and a secondregion having a second outside diameter; an inner tubular memberdisposed within the lumen, the inner tubular member having an innerlumen; an annular space between the outer tubular member and the innertubular member; and a stiffening member disposed within the annularspace.
 14. The device in accordance with claim 13, wherein a manifold isdisposed at the proximal end of the outer tubular member.
 15. The devicein accordance with claim 14, wherein the manifold includes means forcontrolling the stiffening member.
 16. The device in accordance withclaim 13, wherein the stiffening member further comprises a distal headand a proximal tail.
 17. The device in accordance with claim 16, whereinthe stiffening member is movable relative to the outer tubular member.18. The device in accordance with claim 13, wherein the expandableregion comprises a balloon.
 19. The device in accordance with claim 18,wherein the annular space lumen is in fluid communication with theballoon.
 20. The device in accordance with claim 13, wherein the firstoutside diameter is less than the second outside diameter.
 21. Thedevice in accordance with claim 13, wherein the stiffening membercomprises a liquid.
 22. The device in accordance with claim 13, whereinthe stiffening member comprises a gas.
 23. A method for passing aguidewire through a chronic total occlusion, the method comprising thesteps of: placing a guidewire in a blood vessel proximate a chronictotal occlusion; providing a chronic total occlusion device, the chronictotal occlusion device including an outer tubular member having aproximal end, a distal end, and a lumen extending therethrough; an innertubular member disposed within the lumen and having an inner lumen; andan annular space between the outer tubular member and the inner tubularmember; passing the chronic total occlusion device over the guidewiresuch that the guidewire is disposed within the inner lumen; and passingthe guidewire through the chronic total occlusion.
 24. The method inaccordance with claim 23, wherein the chronic total occlusion devicefurther comprise a stiffening member disposed within the annular space.25. The method in accordance with claim 24, wherein the stiffeningmember further comprises a distal head and a proximal tail.
 26. Themethod in accordance with claim 24, wherein the stiffening membercomprises a liquid.
 27. The method in accordance with claim 24, whereinthe stiffening member comprises a gas.
 28. The method in accordance withclaim 24, further comprising the step of actuating the stiffeningmember.
 29. The method in accordance with claim 28, wherein the step ofactuating the stiffening member includes moving the stiffening membertoward the distal end of the outer tubular member.
 30. The method inaccordance with claim 23, wherein the outer tubular member furthercomprises an expandable region.
 31. The method in accordance with claim30, wherein the expandable region comprises a balloon.
 32. The method inaccordance with claim 31, wherein the annular space is in fluidcommunication with the balloon.
 33. The method in accordance with claim30, wherein the expandable region further comprises a first regionhaving a first outside diameter and a second region having a secondoutside diameter.
 34. The method in accordance with claim 33, whereinthe first outside diameter is less than the second outside diameter. 35.The method in accordance with claim 23, wherein the chronic totalocclusion comprises a calcified lesion.
 36. The method in accordancewith claim 23, wherein the chronic total occlusion comprises a stenosis.37. The method in accordance with claim 23, wherein the chronic totalocclusion comprises an atherosclerotic lesion.